An aerogel is a superporous, high specific surface area (≥500 m2/g) material having a porosity of about 90 to 99.9% and a pore size in the range of 1 to 100 nm, and is a material excellent in ultra-light weight, super heat insulation, ultra-low dielectric, and the like. Accordingly, research on the development of aerogel materials as well as research on the practical use thereof as transparent insulation materials, environmentally friendly high temperature insulation materials, ultra-low dielectric thin films for highly integrated devices, catalysts and catalyst carriers, electrodes for supercapacitors, and electrode materials for seawater desalination have been actively studied.
The biggest advantage of the aerogel is that the aerogel has a super-insulation exhibiting a thermal conductivity of 0.03 W/m·K or less, which is lower than that of an organic insulation material such as conventional Styrofoam, and that fire vulnerability and the occurrence of harmful gases in case of fire which are fatal weaknesses of the organic insulation material can be solved.
On the other hand, since the aerogel has very low mechanical strength due to a porous structure thereof, an aerogel composite in which an aerogel is bonded to a fibrous blanket by being impregnated therewith, the fibrous blanket such as an inorganic fiber or an organic fiber, both of which are conventional heat insulation fibers, has been developed. The above aerogel blanket has flexibility so that it can be bent, folded, or cut in any size or shape, and easily handled. Thus, the aerogel blanket is used not only for industrial applications such as heat insulation panels for LNG carriers, industrial insulation materials, spacesuits, transportation, vehicles, and insulation materials for electric power production, but also for household goods such as jackets and sports shoes.
In general, an aerogel is produced by a silica sol preparation step, a gelation step, an aging step, a surface modification step, and a drying step.
However, an aerogel blanket produced by the above conventional method has two disadvantages.
First, in order to prevent the loss of heat insulation performance due to the absorption of moisture in the air by a silica aerogel blanket, the surface of the silica aerogel has been hydrophobized through surface modification to be used. However, in this case, there is a disadvantage in that production time is lengthened, and production cost is increased due to a high raw material cost of a surface modifier.
Second, when such hydrophobic silica aerogel blanket was directly constructed on a high temperature pipe of 500° C. or higher, there was a problem in that a serious bad odor was generated by a volatile organic compound (VOC) and the like, thereby causing pain to workers.
Therefore, the present inventors have developed a hydrophilic silica aerogel blanket for ultra-high temperature insulation, a production method thereof, and a construction method thereof.